The present invention relates to a semiconductor device and, particularly to, an improvement in a semiconductor device having shielding layers provided on opposed surface of a package for encapsulating an (IC) chip.
In a semiconductor device, a shielding layer is employed for electrically and magnetically shielding an IC chip and is thus formed on each surface of a package opposed to each other. Such a device according to a prior art is shown in FIG. 4.
In FIG. 4, an IC chip 32 and a passive element chip 39 are mounted on a wiring substrate 31. The wiring substrate 31 is inserted into a resin case 30 and sealed with a sealing resin 33. A plurality of external leads 37 are provided with being connected to electrodes the wiring substrate 31 and protruded out of the sealing resin 33.
Moreover, a printed conductive pattern 34 serving as a shielding structure is formed on the top of the resin case 30. The printed conductive pattern 34 is connected with the ground (GND) line (not shown) by making an external lead wire 35 attach to the external lead 37 with a solder 36.
According to another prior art as shown in FIGS. 5(A) and 5(B), a wiring substrate 41 on which an IC chip 42 is mounted is entirely soaked in a facing sealing resin 43 and then dried. Thereafter a pin 48 connected to the GND pattern of the wiring substrate 41 is bent so as to contact the mounting surface and moreover soaked in a conductive paste 44 and then dried to form a shielded structure. One of the external leads 47 is connected to the GND, so that the pin 48 is also connected electrically to the GND.
Recently, there has been proposed a semiconductor device in which a part of the package is made of a part of the wiring substrate itself. In this device, the wiring substrate has a recess into which an IC chip is mounted on a bottom of the recess, and a resin is formed to fill the recess and cover the IC chip.
This device, however, has no conductive shield pattern. For this reason, the IC chip is sometimes affected electrically or magnetically by noise.